Modern cancer research requires state-of-the-art cell and tissue imaging technology. These techniques include immunolocalization studies at both the light and electron microscopic levels, live cell studies using molecules tagged with fluorescent probes and introduced by transfection or microinjection, and advanced image recording and analysis. Sophisticated imaging instruments such as electron microscopes, confocal and multi-photon microscopes are not only very expensive, but also require technical assistance for optimal results. For these reasons, it is essential to have a core imaging facility that provides access to both the instruments and technical expertise. Established more than 20 years ago as a departmental service, the Cell Imaging Facility has evolved into a Medical School Core Facility that receives support from the medical school, the Vice President for Research at NU, and the Robert H. Lurie Comprehensive Cancer Center. The Facility's Director, Dr. Teng-Leong Chew, Ph.D., is an expert in light microscopic imaging, especially in advanced live cell fluorescence microscopy. A full time electron microscope technologist is also available to perform routine cell and tissue embedding and sectioning as well as advanced techniques such as immunogold localization, and to train users in these techniques. The facility serves several hundred users from more than 100 research groups throughout the University. Due to the unique expertise as well as the staffs commitment to developing cutting-edge imaging application, the facility has been selected by numerous leading manufacturers as the beta test sites for their instruments and software. More importantly, the facility has been recognized as one of the three National Imaging Centers of Excellence by Nikon, thus benefiting Northwestern immensely through Nikon's gift of several state-of the-art equipments. Approximately 50 percent of total facility usage has been by Cancer Center members with peer reviewed funding. Equipment includes two transmission electron microscopes, two confocal microscopes, one spinning disc confocal, total internal reflection fluorescence (TIRF) microscope, three advanced light microscopes with digital imaging systems and capabilities that include microinjection, epifluoresence, time lapse photography, calcium imaging, FRAP, and FRET. Ancillary equipment includes rotary shadowing evaporators, microtomes, color printers, digital scanner, film recorder, dark room, and computers and software for image analysis.